We have a Brother XN1700 and have been hitting some problems with looping appearing on the bottom of the fabric. We've tried the following, per the instruction manual and some guides on the internet:
- Decreasing the tension
- Increasing the tension (just in case we were confused)
- Rethreading the bobbin and the spool
- Removing and refitting the presser foot holder and the presser foot
- Checked the bobbin hook for any signs of burring
We've never broken a needle on it and the problem seems to have come on gradually in the past few weeks.
Anyone have any thoughts on what could be wrong? I'm happy to disassemble it a bit if needed.